The present application is directed to set screws used for use with fasteners to attach an elongated member to a bone and, more particularly, to set screws with a deformable member that increases the contact with the elongated member to prevent back-out of the set screw from the fastener and/or damage to the elongated member.
Set screws are often used with fasteners to attach an elongated member to a bone within a patient. Examples of fasteners include but are not limited to multi-axial screws, fixed-angle screws, and offset screw connectors. The fasteners may include a receiver with a receptacle to receive the elongated member, and an anchor (e.g., screw, hook) that attaches to the bone. The fasteners may be constructed as a single piece, or may include multiple pieces that are attached together such as a multi-axial screw that includes a receiver body that attaches to a head of bone screw. The elongated member fits within the receptacle of the receiver, and the set screw attaches to the receiver to prevent escape of the elongated member. The set screw may also apply a force to the elongated member to maintain the attachment within the receiver. The fasteners may be configured to receive a variety of different elongated members, including but not limited to rods, cables, and wires.
Often times the receiver is configured to allow the elongated member to be positioned at a variety of angles within the receptacle. This is problematic as the set screw does not fully contact against the elongated member. This may lead to the loosening of the set screw from the receiver and/or backing out of the set screw from the receiver. Additionally, this incomplete contact may damage the elongated member and causing notching or deformation.